body {
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
}

.app {
  display: flex;
  height: 100vh;
  /* width: 100vw; */
}
.header {
  width: 100%;
  background-color: #fff;
}
.sider {
}
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
}
